miR-383 negatively regulates osteoblastic differentiation of bone marrow mesenchymal stem cells in rats by targeting Satb2.

Emerging evidence indicates that microRNAs (miRNAs, miRs) play diverse roles in the regulation of biological processes, including osteoblastic differentiation. In this study, we found that miR-383 is a critical regulator of osteoblastic differentiation. We showed that miR-383 was downregulated during osteoblastic differentiation of rat bone marrow mesenchymal stem cells (BMSCs). Overexpression of miR-383 suppressed osteoblastic differentiation of BMSCs by downregulating alkaline phosphatase (ALP), matrix mineralization, and mRNA and protein levels of RUNX2 and OCN, whereas a knockdown of miR-383 promoted osteoblastic differentiation in vitro. The results of in vivo analysis indicated that inhibition of miR-383 expression enhanced the efficacy of new bone formation in a rat calvarial defect model. Mechanistic experiments revealed that special AT-rich-sequence-binding protein 2 (Satb2) was a direct and functional target of miR-383. Knockdown of Satb2 had inhibitory effects resembling those of miR-383 on the osteoblast differentiation of rat BMSCs. In addition, the positive effect of miR-383 suppression on osteoblastic differentiation was apparently abrogated by Satb2 silencing. Collectively, these results indicate that miR-383 plays an inhibitory role in osteogenic differentiation of rat BMSCs and may act by targeting Satb2.